The effects of combined exercise on working memory in children with attention-deficit/hyperactivity disorder: a...

To evaluate the effects of combined exercise (i.e., aerobic and physical-cognitive exercises) on working memory in children with attention-deficit/hyperactivity disorder (ADHD) and to explore the underlying brain mechanisms using functional near-infrared spectroscopy (fNIRS).

A randomized controlled trial allocated 66 children (mean age 7.3 ± 0.9 years, 55 boys) with ADHD to either an intervention group or a wait-list control group. The intervention group underwent 20 sessions of 90-minute, moderate to vigorous intensity combined exercise six times per week during the summer vacation. Primary outcomes, including working memory and prefrontal cortex activation, were measured using the N-back task (0-back and 1-back) and fNIRS. Secondary outcomes included core symptoms and sleep duration, assessed using the Conner's Parent Symptom Questionnaire and sleep onset/wake time.

Compared to controls, 20 sessions of combined exercise significantly improved the accuracy of children with ADHD on tasks with lower cognitive demands (0-back task) [mean difference: 8.89, 95 % confidence interval (4.25, 13.53), p < 0.001] and nominally improved accuracy on tasks requiring higher cognitive demands involving working memory (1-back task) [mean difference: 6.79, 95 % confidence interval (0.56, 13.02), p = 0.03]. Activation of the right dorsolateral prefrontal cortex (R DLPFC) mediated the improvement in 0-back task performance (β = 5.85, p < 0.05). Additionally, the exercise significantly improved the core symptoms of children with ADHD and extended their sleep duration (p < 0.05).

Twenty sessions of combined exercise during the summer vacation significantly improved 0-back task performance, mediated by the R DLPFC, and nominally improved 1-back task performance.